Phase one involves drilling up to six new polymer injection wells and upgrading the platform. The polymers will make the heavy oil in Captain less viscous, allowing it to flow more easily.

Greta Lydecker, managing director of Chevron Upstream Europe, said: “Operational approval of the Captain EOR project progresses the application of a technology that has demonstrated an improved recovery rate, which can now be applied to other fields and help extend the life of assets.

“Advanced EOR technology in the North Sea supports the UK Government’s strategy of maximising economic recovery of its offshore energy resource.”

A spokeswoman for Chevron said yesterday that the marketing process was expected to take several months and “may or may not result” in a sale.

She added: “We will continue to execute Stage one of the Captain EOR project and mature stage two throughout this process.”

The company has also agreed to sell its 40% operated interest in the Rosebank project, west of Shetland.

OGA operations director Gunther Newcombe said: “This is the 18th project to be sanctioned on the UKCS this year and reinforces the tremendous potential of the basin.

“Chevron’s investment in EOR technology is expected to unlock millions of extra barrels of oil, adding several years to the life of this mature asset, demonstrating strong progress towards Vision 2035.”

Oil and Gas UK chief executive Deirdre Michie said: “Chevron’s investment in this new technology is a great example of how companies are addressing unique, area-specific challenges that can unlock significant remaining reserves and rejuvenate existing infrastructure.”